Selective polymerization of isobutylene



Patented Oct. 27, 1953 SELECTIVE POLYMERIZATION OF ISOBUTYLENE Helmuth G. Schneider, Westfield, and Hans G.

Goering, Elizabeth, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application April 21, 1950, Serial No. 157,400

9 Claims.

This invention relates to the polymerization of isobutylene and more particularly relates to the selective polymerization of isobutylene from its admixture with other low-boiling olefms under such conditions as will result in the production of polymers of narrow ranges of high viscosity and high viscosity index, having molecular weights below 4000 Staudinger.

It is well known that the olefins in a C; out can be polymerized with solid aluminum chloride catalyst to give polymers having Saybolt viscosities at 210 F. of 40 to 20,000. In this process the C4 hydrocarbons are circulated through a bed of solid aluminum chloride, thus providing at all times a large excess of catalyst to olefin in the reaction zone. It is also known that isobutylene can be polymerized with aluminum chloride to give a similar molecular weight polymer. In

polymerizing the isobutylene it has always been 7 considered necessary to remove contaminating olefins such as butene-1, butene-2, etc., if a constant composition product is desired. Furthermore, the products formed cover a broad viscosity range and must be fractionated to desired grades.

It has now been found that by the addition of the catalyst to the C14 hydrocarbon mixturein small quantities, i. e. in amounts slightly in excess of that required to initiate polymerization, substantially complete and selective removal of isobutylene from the C4 out can be obtained. Furthermore, the amount of catalyst can be so adjusted that only part of the oleiins, in the feed, are polymerized and thus the viscosity of the product can be controlled. The reaction products may be steam stripped to give the desired product since only a relatively small proportion of light ends are formed. Vacuum fractionation is not necessary.

As source material for the mixture of C4 hydrocarbons found suitable for the practice of this invention, use is made of the olefin-containing gases generally produced in the thermal cracking of petroleum crude oils, distillates, or residuum, although it will be apparent that other olefincontaining materials may serve as well. These olefin-containing cracking still gases are iractionated or otherwise treated for the recovery of the four-carbon atom olefins, including butene-l, butene-2, and isobutene and the associated saturated hydrocarbons. Such a fraction may also contain other hydrocarbons, both saturated and unsaturated in small amounts. The following is an analysis of a typical C4 cut:

Percent by volume The polymerization reaction is preferably, although not in all cases, carried out at temperatures below atmospheric. Generally, temperatures excessively below atmospheric are of no particular benefit. Ordinarily temperatures are employed within the range 40 F. to 120 F., corresponding to the range of about 40 C. to about 50 C.

Catalysts suitable for the polymerization reaction according to this invention include solid catalysts of the Friedel-C'rafts type, such as aluminum chloride, aluminum bromide, titanium tetrachloride, uranium chloride, zirconium tetrachloride and the like. The catalyst is added in small quantities, slightly in excess of that needed to initiate the reaction. The reaction may be carried out in any desired manner so long as a large excess catalyst is not used. A very simple and practical method of operating consists in carrying out the reaction at the boiling point of the C4 cut (0 C.) using a reflux condenser to return the vaporized hydrocarbon mixture to the reaction zone.

The amount of catalyst added must be controlled in order to selectively remove the tertiary olefin. The catalyst is best employed in the solid form but it may also be used as a solution in a solvent which forms no complex with the catalyst. Suitable solvents are the alkyl halides such as methyl and ethyl chlorides. VIhen the catalyst is used in the solid form the amount may vary between 0.01 and. 2.15% by weight of the feed.

When a dissolved catalyst is used, the amount of catalyst added is much smaller since the catalyst is much more efficient. In this case the 3 range is between 0.005 and 1.0% by weight of the total olefins in the feed.

One of the fundamental advantages of the present invention lies in the fact that it results in the preparation of a product having a very specific viscosity range without the necessity of fractionation. The prior art processes using large quantities of aluminum chloride result in the preparation of polymers having a wide viscosity range. These must be separated by fractionation to give a specific viscosity product. According to the present process a desired viscosity product can be obtained by control of the reaction time, catalyst concentration, temperature, and content of isobutylene in feed.

The reaction is usually complete in five to ten minutes. Continued reaction increases the yield only slightly and causes a slow viscosity lowering.

The polymer yield and viscosity vary little over a catalyst concentration of range of 0.01% to 1.67% based on the feed, but catalyst concentrations up to 2.15% based on the feed are suitable.

Polymer yield increases but viscosity decreases with increasing temperature. Both polymer yield and viscosity increase as the concentration of the isobutylene in the feed is increased.

The process may be carried out either batchwise or continuously. Generally continuouspolymerization gives lower yields than batch when polymerizing to a given viscosity and gives polymers of lower viscosity than those made. batchwise when polymerizing to a given conversion level. Conversion is the most important variable outside of the catalyst concentration in obtaining the desired viscosity product.

The invention is desirably carried out in the following manner. A C4 naptha of known composition is first charged to a precooled reactor and the desired operating temperature attained, either by internal or external cooling. The catalyst is then added in very slight excess and the reaction allowed to continue for five to ten minutes or more as desired. At the end of this time the batch (with or without filtration) is contacted with water to neutralize the catalyst. Unreacted hydrocarbons are stripped from the product' solution by heating over water to 100 C. Higher boiling light ends are steam stripped from the polymer product at 150-200 C. and the polymer is identified by viscosity determination.

When the above process is carried out continuously the feed is charged continuously to a refluxtype reactor or a reactor fitted with external or internal refrigeration with an overflow tube to maintain a constant reactor volume. The conversion level in the reactor is determined by the high boiling polymer content of a spot sample of the efliuent polymer solution, or by olefinic analysis of the spent naphtha. The formation of polymer is controlled by regulating the rate of addition of the catalyst. The efiluent polymer solution may be filtered and then immediately treated with water or alcohol to kill the catalytic reaction or may be contacted with alcohol and/or water directly after leaving the reaction zone.

The process of the present invention is applicable for the preparation of a desired narrow range viscosity product from either a pure or impure feed. When employing an impure feed such as a C4 naphtha, the process is selective. Isobutylene is first polymerized, then butene-l, and finally butene-2. If it is desired to polymerize only the isobutylene, the amount of catalyst and time of contact is controlled to selectivelypolymerize the material. After the isobutylene has been removed, the spent C4 naphtha can be further contacted with catalyst to polymerize the butene-l or the amount of catalyst originally used can be increased and the contact time continued until both isobutylene and butene-1 have been polymerized. In this latter case the amount of catalyst initially used is about 5%. When selectively polymerizing butene-l, the i-sobutylene may be removed in any manner known to the art, such as by extraction with sulfuric acid, etc. prior to contacting with the A1013 catalyst.

In order to properly understand the present invention, the following examples are given:

EXAMPLE I The following data illustrates the small amount of solid A1013 catalyst needed at the C4 boiling point (0 C.) to yield the high viscosity type polymers:

Table 1.-E 7ect of catalyst concentration on polymerization of C4 naphtha A. OPERATING CONDI'II %}l: Z )Sl IAND PRODUCT EVALUA- Equipment-5 liter, round bottom, 3 neck flask- Attachments-Dry Ice-a1coh01 reflux condenser, agitator (mercury seal type), low temperature thermometer.

Charge2 liters (i200 gms.)

analysis) Catalyst-solid AlCla (powdered) refinery C4 naphtha (see below for Temp.t-0 O. Pressure-atmospheric (l. e. reactions run at boiling pom Time-30 min. 30

Product evaluation Steam dis tillcd at Catalyst Catalyst 200 Run h l Yield (wt. eificiency 4 No percenton. (gms.poly- Percent c it;

' added total 04) met/gm. polymer Os d catalyst) oil (per 0 5 Game total 04) cent on polymer crude (centis tokes polymer) at 210 F.)

B. ANALYSES OF 04 NAPHTHA FEED Liquidvoi. Component percent Ca U Isobutanc 21.0 n Butane 48. 0 Isobutylene 10. 6 Butene-l 9. 0 Cis butene-2 3. 5 Trans butene 5. 8 Butadienc 0. 5 C0 C 1.6

"iliters C4 naphtha used in this run. Two gins. A1011 reacted with 2 liters C4 naphtha for 30 min. Then added 2 liters O4 naphtha and reacted for 30 min. additional.

From the data in Table 1 it is evident that the reaction stops with the depletion of the tertiary olefin.

EXAMPLE II To show the criticalness of the quantity of catalyst in effecting selective polymerization, the following data are given wherein AlCls in a non-complex forming solvent isused.

5 Table 2.E'1Tectfof liquid catalysts-Alma dissolved in ethyl chloride A. OPE RATING CONDITI gigSqAND-PRODUGT EVALUA- Eauipment-liliter, round bottom, 3 neck flask Attachments-Dry cea%cohol reflux condenser, agitator, low temperature thermome er.

Charge-2 liters (1200 gms.) refinery C4 naphtha (see part B for analyses).

Catalyst--5 gmaAlCla/IOO mi. ethyl chloride (solution) B. ANALYSES OF SPENT NAPHTHA PERCENT) Run N 6 7 Polymer yield (Wt. percent) 13.6 20. 2

Feed Component charged 01 0 0 Isobntane 21. 0 24. 4 23. n-Bnhana 48. 0 54. 4 58. Isobutylene 10. 6 0. 0 0. Butane-1-; 9. 0 8. 9 2. C15 butene- 3.5 4.6 5. Trans butane-2- 5. 8 6. 8 7. Butadiene 0. 0. l 0. Cri- 1. 6 1. 3 2.

drop in catalyst efficiency with increasing" amounts of added catalyst is due to increased resistance to polymerization of butene-l and butene-2 as compared to isobutylene. A comparison of the spent feed in runs 6 and 7 shows that all of the isobutylene and practically none of the other olefins were polymerized when only 0.083% of catalyst was used but that increased amounts of catalyst over this resulted in increasing amounts of the other olefins (butene-l) being polymerized.

EXAMPLE m The following data illustrate the effect of contact time on the polymerization of isobutylene in C4 naphtha when the amount of feed and catalyst are held constant.

6 Table 3.E'17ect-on contact time on polymerizatz'on of C4 naphtha A. OPERATING CONDITIONS AND PRODUCT EVALUATION Equipment-5 liter, round bottom, 3 neck flask. Attachments-Dry Ice-alcohol reflux condenser, agitator (mercury seal type), low temperature thermometer.

Oharge2 liters (1200 gms.) refinery C4 naphtha (see part B for analysis). Catalyst-0.83% solid A101: (powdered) based on total 04 naphtha.

Temilggo c. Pressure-atmospheric (i. e. reactions run at boiling Product evaluation Steam distilled at 200 0. (gtialyst Yield (wt. 9 Run Time ms. Percent percent on Viscosity of N (mm') total 04) g 3 steamed catalyst) (percent f on crude stok es at polymer) B. ANALYSES OF SPENT NAPHTHA (LIQUID VOLUME PERCE Run N 10 11 13 Contact time --min 10 30 180 Polymer yield (wt. percent) 11.4 12.0 15.3

Component g g 0 o 0 0 21. O 22. 8 21. 9 23. 6 48. 0 57. 2 56. 4 57. 4 10. 6 0. 5 0. 4 0. 4 9. 0 9. 4 10.6 7. 3 3. 5 3. 2 3. 2 4. 0 5. 8 5. 8 6. 3 7. 2 '0. 5 0. 1 0.3 0. 1 l. 6 1.0 0. 9 0

Part A of the above data shows that the yield of crude polymer varies but little with extended reaction time at the C4 naphtha boiling point, 11 to 15% in a span of 10 to 180 minutes. The reaction is quite rapid for the first 5 to 10 minutes. An examination of the products shows that there is a gradual reduction in the viscosity of the steamdistilled polymer with reaction time. Also the quantities of light polymer oils increases. The selective nature of the process is also indicated. Isobutylene is polymerized during the first rapid stage of the reaction (5-10 minutes). Following this the secondary olefins are attacked, butene-1 polymerizing faster than butane-2.

EXAMPLE IV The following data illustrate the effect of temperature on the products:

Table .LQEfiect of temperature rm polymerizafloor of C4 naphtha A. OPERATING CONDITIONS AND PRODUCT EVALUATION Equipment-5 liter, round bottom, 3 neck 'flask-attachments reflux condenser, Dry Ice-alcohol external cooling bath, agitator, low temperature thermometer.

Char e 2) liters (1200 gins.) refinery O4 naphtha (see part B for ans 5 s Oataly st-0.33% solid AlCla (powdered) based ontotal G1 naphtha.

PRBSSUIB-ii-IIIIOSPIIGTIC.

Product evaluation Steam distilled at 200 F.

Yield Catalyst Ti T (wt. t effi(ciency iff g f -me emp.percen gms. (min) 0. on polymer] gf g g total (perpolymer catalyst) cent (centre "f on Stokes at crude 210 F.) p ymer.)

Part (A-l):

J- re gggg 88%38 B. ANALYSES OF SPENT NAPHTHA (LIQUID VOLUME PERCENT) Run Run Component Feed 20 i9 Ca 0 0 0 Isobutane- 18. 7 22. 1 21. 7 n-Butane 46. 7 56. 2 49. 9 Is0butylene 11. 9 0.3 6. 7 Butene1 9. 2 '10. 1 11.1 015 butene-2. 3. 8 3. 8 4.0 Trans butene-2 5. 8 6. 5 6. 0 Butadiene.-- 0. 4 0. 2 0. 1 C 3. 5 0. 8 0.5

The above data show that the polymer yield varies with temperature, increasing from 0.3% at 25 C. to 13.9% at l C. for a reaction time of 60 minutes. The viscosities at 210 F. of the products vary inversely with reaction temperature from a viscosity of 35,000 cs. at 210 F. for areaction temperature. of -.1.5.C. to 5,300 cs. at 210 F. for a reaction at .1 C. It is also evidentthat the Speed of the reaction is reduced asthe reaction temperature is decreased. Thus by increasing the reaction time at -25 C. ior 1 to 4 hours, the yield increased from 03 to 7.0%. The viscosity of the product obtained at this temperature was 103,000 cs. at 210 F. At -15 C. the yield of polymer increased from 6.9% to 13.8% by increasing the reaction time from 1 to. 3 hours. The material produced at this temperature had 35,000 viscosity at 210 F. for one hour reaction and 26,000 cs. viscosity for 3 hours reaction time. The analysis data show that the tertiary olefins are polymerized selectively at all temperatures used.

EXAMPLE V The data of Table 4 are concerned primarily with the polymerization at temperatures at or below the boiling point of the naphtha at atmospheric pressure. The above conclusions are further affirmed at higher react-ion temperatures 75 where the reaction is run-in the liquid phase. der pressure. Such data are given in Table 5. Here the reaction is conducted at temperatures between 2'7? C. and 38 C. It is to be noted that here again the viscosity of the product de-' creases with increasing temperatures; also that the selectivity of polymerization can be controlled. In 'runs 21 and 22 for example only the isobutylene has reacted in 20 minutes con-- tact time whereas at higher temperatures at the same contact time the isobutylene, the butene-l, and some butene-2 has reacted.

Table 5.-E,(7ect of elevated temperature on poly merization of .04 naphtha A. OPERATING CONDITIONS AND PRODUCT EVALUATION Equipment-5 liter, metal-jacketed reactor, tap water cooling, agitator, room temperature thermometer. Charge--2 liters (1200 gms.) refinery C4 naphtha,

2Q Catalyst-0.33% solid A1013 (Ohio Apex-subllmed) based on total C4 naphtha. Contact Time minutes.

V scosity of steamv T Presdisltilled 1' amp. sure, yum! Run o. lbs/sq. (centiin. stokes at 210 F B. ANALYSES OF SPENT NAPHTHAS (LIQUID VOLUME PERCENT) Component Feed gi gi 16. 9 21.4 17.5 19.1 35. 5 45.1 44.5 51.6 54.3 13.6 0.3 0.7 1.3 0.2 12. 4 l0. 1 12.1 3, .9 2.0 14. 6 16. 6 l8. 1 1.6.1 12. 3

EXAMPLE VI Thefollowing data are given to Show the effect of the, isobutylene concentration of the feed on the viscosity of the product.

Table sz Efiect of isobutylene concentration of feed on polymerization of C4 naphtha A. OPERATING CONDITIONS AND PRODUCT EVALUATION Equipment-'5 liter, round bottom, 3 neck flask. Attachments 0 pomt).

Time-30 min.

Product evaluation steam distilled at 150 0. Percent Catalyst Run Isobutylene Yield (wt. efficiency N0 1nf eed percent on (gms. poly- Percent f (liquid vo t tal 4) met/gm. p lymer 2 percent) catalyst) oil (percent on p0 crude centistokcs a polymer) t F Table 6.-E17ect of isobutylene concentration of feed on polymerization of C4 naphtha-Continued B. ANALYSES OF FEEDS (LIQUID VOLUME PERCENT) RunNo 25 26 Component:

1 Same feed as used for run No. 26 was used to make up the feeds containing higher concentrations of isobutylene. This was done by merely adding more isobutylene to the known plant stock.

EXAMPLE VIII The following data illustrate the efiect of using aluminum bromide instead of aluminum chloride as the catalyst:

Table 7 .4. OPERATING CONDITIONS AND PRODUCT EVALUATION Equipment-5 liter, round bottom, 3' neck flask. Attachments- Dry Ice-alcohol reflux condenser, agitator, low temperature thermometer.

Charge-2 liters (1200 gms.) refinery C4 naphtha (see part B for an ysis). TempTO" C. Pressure-atmospheric (reactions run at boiling point Time-30 min.

Product evaluation C t Cata- Steam distilled at lyst 200 0. 3 Yield an- R 1 (wt (Wt- C(ienc P t un pergins. ercen No. Type of g cent polypoly. Visc. of 3 on mer/ oil (per- Polymer total 04) gm. cent on (centi- O catacrude stokes at lyst) poly- 210 F.)

mer)

30 Commercial 0. 83 12. 5 15.0 8 3, 630 8L... Refined 0.83 11.8 14.2 8.5 4,100 32...- Large 1umps O. 17 3.8 22. 5 4, 300 33..-. Powder (ground). 0. 17 10.0 60.0 9. 0 1,810

B. ANALYSIS 0F 01 NAPH'IHA FEED Component ggggg (1. 0 Isnhntann 21,0 n-Butane. 48. 0 Isobuty l0. 6 Butane-l 9.0 Cis -2- 3. 5 Trans butane-2 5. 8 Butadlene 0. 5 0 1.6

The above data show that aluminum bromide is as good as aluminum chloride as a catalyst.

EXAIVIPLE VIII A series of experiments were carried out in which the feed was charged continuously and 10 product was removed continuously. The effect of varying conversion level (per cent of unreacted isobutylene in the spent naphtha) on the product yield and quality is shown in the following data:

Table 8.-Efiect of varying conversion level on continuous polymerization of C4 naphtha A. OPERATING CONDITIONS AND PRODUCT EVALUATION (N0rE.-Data shown for continuous runs was taken at relatively constant conversion levels only.)

Equlpment-1 liter glass, reflux type overflow reactor, run with 600 cc. holdup. Attachments-liquid eed blow case reflux condenser, thermometer, agitator, product solution receptacle.

Feedrefinery Cr naphtha (see part B for analysis).

Catalyst-solid A101 (sublimed).

Temp.0 C. Pressure-atmospheric (i. e. polymerizations run at boiling point).

Contact Time7.5 min. (8 reactor turnovers/hr).

4 Product evaluation Steam gdstlled at 1 32202. Catalyst Run percent Yield (Wt. efllciency N0 A1013 percent on (gms.poly- Percent Viscosity on total 04) met/gm. polymer Steamed total C4) catalyst) 22 98; polymer crude (centrsgokes polymer) at 210 F.)

B. ANALYSES or SPENT NAPHTHA (LIQUID VOLUME PERCENT) The above data show that comparatively high viscosity polymers (2240-3200 cs. at 210 F.) are realized when running with feeds containing 11.5% isobutylene at conversion levels below 11% At slightly higher levels, however, much lower viscositymaterial (450-490 cs.) is prepared along with larger fractions of steam-volatile polymer oils. I

EXAMPLE IX A series of experiments was carried out similar to Experiment VIII except that the isobutylene concentration in the feed was varied. The results of these experiments are shown in the following data:

if more 9.-Efie'c't isobutylene coc on-mitten or feed on the continuous polymerization of C4 naphtha A. OPERATING CONDITIONS AND PRooUo'r EVALUATION (Norm-Data shown for continuous runs was taken at relatively constant levels only.)

Eduipineiitl liter glass, refiiiic' tjiidpvrfioiif reactor r iliwlth 500 cc. holdup. Attachments-1 1; liquid feed bloii case, reflux condenser, thermometer, agitator, product solution receptacle.

Feedrefinery O4 naphtha (see part B for analysis).

oatalystTsolid A101; Ohio Apex-sublimed) Temp.0 G. Ptessure''tn1ospheric (i. e; polymerizations run at boiling pt.) Contact Tlme7.5 min. (8 reactor turnovers/11L).

i i-tenet evaluation Steam distilled at 150 F. Catalyst IsoG conc. Yield i1111 feedl (wt.- t (wt. t (gins y Percent 'qui percen percen D0 17-. N vol. A101: on total g-g mei' oil percent) on total 04) [381531 i (p 4) y cent on Y 4 crude (cent stokes V at 210 F.) mer) 30- 0. 2 0.31 4. 9 1'5. 9 8. 7 400 34. 11-. 0. 33 9. l 27. 2 l. 2 3, 200 39.. 12. 5 0. 23 10. 1 47. 3 l. 2 3, 800 40. 7 0. 33 13. 9 42. 2 1. 8 3, 300 41 20. l 0. 35 17. 5 50. 1 1. 4 7, 200

B. ANALYSES. or FEEDS .AND sPENT NAPHTHAS (LIQUID VOLUME PERCENT) RunNo as 04 30 40 41 u 4 a u is F a :5 l e 0% in to a: m n co Component:

0 --0.Q 0.5.0.0 0.0 0.0.0 I'sbbutan 419.511.417.510.019;Q23.110718.3 15.0170 n-Butan 5l.658.149;552.043.748.546.3515.644.2556 Isobutylen 0.2 1.711.5 4412.5 4415.7 2.4 20.1 3.3 Butene1 .-10.010.1 0.2105114 11.710.510.13 0.0 0.9 Oisbutene'2 3.9 4.8 4.0 4.6 4.8 4.7 3.7 4.0 as 5.1 'rra'nsoiitene-a. 0.7 0.9 0.0 7.1 7.0 7.4 0.0 7.4 5.0 7.7 Butadienenaun 0.3 0.3 0.3 0.4 0.4 0.4 0.4 0.2 0.3 0.4 06+ 0.0 0.80.4 0.8 1.3 0.1 0.7 0.0 1.1 1.0

The above data show that the yield of polymer increases from 4.9 to 17.5% and polymer viscosities range from 400 to 7,200 cs. as the isobutylene concentration is increased from 6 to The data obtained in Examples 8 and 9 iridicate how a given viscosity product Gan be obteined by correlating the amountof isobutylene in the feed with the isobutylene in the spent naphtha (conversion). This correlation shows for example that a 660 cs. product may be pre pared from a feed containing 10% isobutylene at avery high; conversion level of about 0.5% isobutyle'ne iii the spent naphtha. Uh the contrary,

if there is only 7% isobutylene in the feed their the conversion must be very low (5% isobutylene in spent naphtha).

Having thus described the invention what is claimed as new and useful anddesired to be secured by Letters Patent is:

1. The process of selectively polymerizing isobutylene from its admixture with other olefins of 3 to 5 carbon atoms which comprises cooling and liquefying a hydrocarbon material consisting substantially of normal butenes, isobutene, and butane, the amount of isobutene being about 6' to 20% f the entire reaction mixture, n refluxing the cooled hydrocarbon material at 0 C.

based on the feed, of solid, powdered, anhydrous 12 aluminum chloride, whereby substantially som plete polymerization of the isobutylene is obtained but substantiall no other butenes, are polymerized.-

2. The process of selectively polymerizing isobutylene from its admixture with other olefins which comprises cooling and liquefying a hydrocarbon material consisting substantially of nor-- mal butenes, isobutene and butane, the amount of isobut-ene being about 6 to 20%, refluxing the cooled hydrocarbon material at 0 C. in the presence of 0.005% to 0.083% by weight, based onthe total feed of aluminum chloride, dissolved in ethyl chloride, whereby substantially complete polymerization of the isobutylene is obtainedbut substantially no other butene is polymerized. I

3. The process or selectively polymerizing 1311-" tene-l from its admixture with is and trans butene-Z, which comprises cooling and liquefying a hydrocarbon material consisting of butane-1. and 61S and trans bute'ne-2 as substantially the only olefins present, refluxing the cooled hydrocarbon material at 0" C. in the presence oi 5% by weight based on the feed or solid "powdered aluminum chloride, whereby substantially com plete polymerization of butene-l is obtained but substantially no briteri-Z is polymerized.

4. The rocess or selectively olymerizing isobutylene from a petroleum hydrocarbon c4 irac= tion having the following analysis (by volume):

which comprises cooling and liquefying said C4 fraction, and refluxing it at about 0 C. and at atmospheric pressure; in the presence of 0.05% to 0.35% by weight,- based on the feed, of sublimed anhydrous aluminum chloride powder, for a i=- action time of 5 to minutes,- whereby substantially complete polymerization of the isobutylene is obtained, to produce a viscous oily polymer, but substantially no other butenes are polymerized. 4 I I 5. The process of selectively polymerizing iso= butylene from its admixture with other olefiiis which comprises bringing into contact with a catalyst, chosen from the class consisting of solid powdered aluminum halide, said aluminum halide being present in proportions of 0.05% to 0.083% based on the feed, and aluminum halide dissliid in ethyl hlfir'id, said aliiifiifiiiffi l'lalidethyl chloride solutiqn being present in propertions of 0.005% to 0.083%, based on the feed, an initial hydrocarbon materiai'consisting substantially entirely of hydrocarbons of 3 to 5 carbon atoms per molecule iii majorart, the said initial hydrocarbon material containing both normal olefin and isoolefins and being accompanied by corresponding saturated aliphatic hydrocarbon, at a temperature or about (3.,150 about 0., whereby substantially polymerization of isobutylene is obtained but substantially no other olefins are polymerized.

6. The process of selectively polymerizing isobutylene from its admixture with other olefins which comprises bringing into Contact with a 13 catalyst. chosen from the class consisting of solid powdered aluminum chloride, said aluminum chloride being present in proportions of 0.05 to 0.83% by wt., based on the feed, and aluminum chloride dissolved in ethyl chloride, said dissolved aluminum chloride being present in proportions of 0.005% to 0.083% based on the feed, an initial hydrocarbon material consisting substantially of butene-l, butene-2, isobutylene and butane at a temperature of 25 C., to +38 C., for a time of 30 minutes, whereby substantially complete polymerization of the isobutylene is obtained but substantially no other butenes are polymerized.

7. The process according to claim 6 in which the resulting isobutene free mixture of butene-l and butene-2 is further contacted with a sufficient amount of aluminum chloride to make a total of 5%, whereby the butene-1 is substantially completely polymerized lbut substantially no butene-2 is polymerized.

8. The process according to claim 7 in which the temperature is raised above 0 C., after all the butane-1 has been polymerized, for a time sufficient to polymerize all of the remaining olefins present consisting essentially of cis-butene-Z and trans-butene-Z.

9. The process of selectively polymerizing isobutylene and butene-l from their admixture with other olefins which comprises cooling and lique fying a C4 petroleum hydrocarbon fraction con taining butene-l, butene-2, and isobutylene, and refluxing the cooled hydrocarbon material at 0 C. in the presence of 0.05 to 0.83% by weight of powdered aluminum chloride whereby substantially complete polymerization of the isobutylene is obtained, then adding a sufli-cient amount of additional aluminum chloride to bring the total amount up to 5% by weight, and continuing the polymerization for a period of time up to minutes whereby substantially complete polymerization of butene-l is obtained but substantially no butene-2 is polymerized.

HELMUTH G. SCHNEIDER. HANS G. GOERING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,065,474 Mueller-Cunradi et a1 Dec. 22, 1936 2,084,082 Fitch June 15, 1937 2,084,50l Otto et al. June 22, 1937 2,320,256 Bailey et a1 May 25, 1943 2,387,784 Thomas et a1 Oct. 30, 1945 2,458,977 Carmody Jan. 11, 1949 

1. THE PROCESS OF SELECTIVELY POLYMERIZING ISOBUTYLENE FROM ITS ADMIXTURE WITH OTHER OLEFINS OF 3 TO 5 CARBON ATOMS WHICH COMPRISES COOLING AND LIQUEFYING A HYDROCARBON MATERIAL CONSISTING SUBSTANTIALLY OF NORMAL BUTENES ISOBUTENE, AND BUTANE, THE AMOUNT OF ISOBUTENE BEING ABOUT 6 TO 20% OF THE ENTIRE REACTION MIXTURE, AND REFLUXING THE COOLED HYDROCARBON MATERIAL AT 0* C. IN THE PRESENCE OF 0.05% TO 0.83% BY WEIGHT, BASED ON THE FEED, OF SOLID, POWDERED, ANHYDROUS ALUMINUM CHLORIDE, WHEREBY SUBSTANTIALLY COMPLETE POLYMERIZATION OF THE ISOBUTYLENE IS OBTAINED BUT SUBSTANTIALLY NO OTHER BUTENES ARE POLYMERIZED. 